Thermostatically-controlled heating plug



Dec. 18, I928.

E. G. K. ANDERSON THERMO STATICALLY CONTROLLED HEATING PLUG Filed April 14, 1927 /aw\\@x MWWMWMMW r i w v v A gwvgmwk kwm Z &

I. m%% aw L+ ym y Patented Dec. 18, 1928. I

UNITED STATES-- 1,696,146 PATENT OFFICE.

mms'r e. x. umnnson, or EVANSTON, ILLINOIS, ASSIGNOB 'ro APPLETON ELECTRIC comm, A conroanron or rumors.

TEERMOBTATICAIiLY-CONTROLLED HEATING PLUG.

Application ma April 14, 1927. has no. 188,828.

The present invention, specifically considered, relates to a sto per for a hot water bottle or the like and lias for its object to produce a simple and novel construction by '5 means of which the temperature of liquid in the bottle may automatically be maintained at a uniform temperature.

In carrying out my invention I make use of a plug having se arated terminals adapted to dip into the' iquid to be heated, and -,containing..a thermostat that will open an electric circuit when a predetermined maximum of temperature is reached and thus shut off the ener for supplying the heat. Therefore, since t e plug may be used for other purposes than as a stopper for a bottle or other container, my invention may be said to have for its object to produce a simple and novel liquid heater containing a. thero most-atic controller for regulating the heat.

The various features of novelty whereby my invention is characterized will hereinafter he pointed out with particularity int the claims; but, for a full undertanding of ..my invention and of its objects and advantages, reference may be had to the 01- lowing detailed description taken in connec-- tion with the accompanying drawing, wherein: Figure 1 is a side elevation through a device arranged in accordance with the preferred form of my invention; Fig. 2 1s a central longitudinal section, on a larger scale on a lane at right angles to that of Fig. 1; an Fig. 3 is a section on line 3-3 of Fi 2.

Re erring to the drawing, 1 represents a bod or plug of insulating material which, if t e device is to be employed as a stopper for a bottle or other container, has a screwthreaded lower portion as indicated at 2. The extreme lower end of the plug is in the form of a tube or shell 3 smaller in diameter than the screw-threaded ortion. Within this shell is a terminal 4 in t e form of a sleeve, the u per end of which extends into the body 0 the plug. Openings or windows 5 and 6 are formed in the compound annular wall composed of the members 3 and 4, at diametrically opposite points. There is a second terminal 7 in the form of a comparatively heavy metal rod or post lying at the long axis of the annular terminal and projecting up into the body of the plug. The lower end of the terminal 7 pref- Y screw 11. When the temperature of the ther 'Mechanically and electrically connected-to the terminal 4 is a switch blade 8 that extends upwardly above the top of the plug. i

There is a similar switch blade 9 for the 7 terminal 7, but this switch blade is not permanently connected to its terminal, the connection being adapted to be automatically made and broken to control the heat when the device is in use.

There is a chamber or well 10 opening down through the top of the plug at the center. The upper end of the terminal 7 extends into the bottom ofthis chamber or well. A suitable contact piece extends from the blade 9 into one side of the chamber or well; this contact piece being conveniently so mthe' form of a small screw 11 extending through a screw-threaded hole in the switch blade; the plug having in one side a hole 12 through which the screw maybe inserted; and the hole being filled with suitable plastic insulating material after the screw has been properly adjusted. Rising from the to of the terminal 7 is a thermal element 13 w ich, when its temperature is below a predetermined maximum, engages with the contact mal element rises above a predetermined maximum value it bends in the well known manner soas to swing out of.engagen1ent with the contact screw, thus interrupting the flow of current if there has been current flowing. The terminal 7 must conduct heat to the thermal element, and it is therefore required to be of heat conductive material as well as being electrically conductive.

The remainder of the device consists simply of a head on the end of a cord or cable 14, whose purpose is to form a quickly detachable connection between the switch blades 8 and 9 and a source of electrical energy. In the arrangement shown, the

head consists of a lower body 15 of insulating material and an upper body 16 fastened together by a screw 17. The member 15 has pockets extending up from the hot tom, as indicated at 18 and 19, to receive the projecting ends of the switch blades 8 and 9. Resilient contact fingers 20 and 21 extend from the member 16 down into the pockets 18 and 19 in position to engage trictionally with the switch blades when the head is pushed down over the blades.

The upper part of the plug is preferably flattened at two opposed sides, as indicated at 22 in Fig. 1, thereby producing a more or less rectangular head that may be gripped in the fingers for the purpose of screwing the plug into or out of a bottle or the like.

In using the device, it is placed so that that part below the screw-tln'eaded section is surrounded by the liquid to be heated. hen the current is turned on it passes between the terminals 4: and 7, the liquid acting as a part of the circuit. The resistance of the liquid is considerable and therefore heat is developed. The terminals of course become as hot as the liquid in contact with the same and, as the temperature of the middle terminal 7 rises and falls, so also does the temperature of the thermal element 13. As long as the temperature of the liquid is below a. predetermined maximum the thermally controlled switch remains closed but, when there is an increase in the temperature above such maximum, the switch is automatically opened and the flow of current interrupted.

\Vhen a liquid is heated it expands, so that the hotter liquid in a body rises to the top and cooler liquid settles. In the use of my improved device, the liquid within the annular space at the bottom of the device rises as it is heated and flows laterally out through the windows 5 and 6, other cooler liquid being pressed up into the bottom of this annular space by the greater liquid head on the outside where the top of the liquid is cooler than it is within the annu lar space. In this way a circulation of the liquid in a bottle or the like is maintained. so that the entire liquid contents will he kept warm or hot as the case may be.

IVhile I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claim.

I claim:

A heating stopper for a liquid container comprising a stopper body of insulating material, a tubular terminal projecting downwardly from said body, the material of the body being continued down around said terminal and underneath the free edge of the latter, a second terminal extending downwardly from said body at the center of the tubular terminal and having its lower end lying at a considerable distance above the lower end of the tubular terminal.

In testimony whereot, I sign this speci- ERNST G. K. ANDERSON.

, fication. 

